Prevent any rotation while seamless rotation is pending.

Various errors occur when using even the normal rotation animation while
seamless rotation is pending. So we just defer the rotation like we do
for the normal animation. Since we are doing this, we need to track
when seamless rotation finishes so we can perform a post-rotate
rotation if required.

Bug: 31749456
Change-Id: I99f189306c690ce868496460e9ca7dcc95e4ccdc

services/core/java/com/android/server/wm/WindowManagerService.java

@@ -654,6 +654,12 @@ public class WindowManagerService extends IWindowManager.Stub
     WindowManagerInternal.OnHardKeyboardStatusChangeListener mHardKeyboardStatusChangeListener;
     SettingsObserver mSettingsObserver;
 
+    // A count of the windows which are 'seamlessly rotated', e.g. a surface
+    // at an old orientation is being transformed. We freeze orientation updates
+    // while any windows are seamlessly rotated, so we need to track when this
+    // hits zero so we can apply deferred orientation updates.
+    int mSeamlessRotationCount = 0;
+
     private final class SettingsObserver extends ContentObserver {
         private final Uri mDisplayInversionEnabledUri =
                 Settings.Secure.getUriFor(Settings.Secure.ACCESSIBILITY_DISPLAY_INVERSION_ENABLED);
@@ -6821,6 +6827,38 @@ public class WindowManagerService extends IWindowManager.Stub
             return false;
         }
 
+        final DisplayContent displayContent = getDefaultDisplayContentLocked();
+        final WindowList windows = displayContent.getWindowList();
+
+        final int oldRotation = mRotation;
+        boolean rotateSeamlessly = mPolicy.shouldRotateSeamlessly(oldRotation, mRotation);
+
+        if (rotateSeamlessly) {
+            for (int i = windows.size() - 1; i >= 0; i--) {
+                WindowState w = windows.get(i);
+                // We can't rotate (seamlessly or not) while waiting for the last seamless rotation
+                // to complete (that is, waiting for windows to redraw). It's tempting to check
+                // w.mSeamlessRotationCount but that could be incorrect in the case of window-removal.
+                if (w.mSeamlesslyRotated) {
+                    return false;
+                }
+                // In what can only be called an unfortunate workaround we require
+                // seamlessly rotated child windows to have the TRANSFORM_TO_DISPLAY_INVERSE
+                // flag. Due to limitations in the client API, there is no way for
+                // the client to set this flag in a race free fashion. If we seamlessly rotate
+                // a window which does not have this flag, but then gains it, we will get
+                // an incorrect visual result (rotated viewfinder). This means if we want to
+                // support seamlessly rotating windows which could gain this flag, we can't
+                // rotate windows without it. This limits seamless rotation in N to camera framework
+                // users, windows without children, and native code. This is unfortunate but
+                // having the camera work is our primary goal.
+                if (w.isChildWindow() & w.isVisibleNow() &&
+                        !w.mWinAnimator.mSurfaceController.getTransformToDisplayInverse()) {
+                    rotateSeamlessly = false;
+                }
+            }
+        }
+
         // TODO: Implement forced rotation changes.
         //       Set mAltOrientation to indicate that the application is receiving
         //       an orientation that has different metrics than it expected.
@@ -6849,8 +6887,6 @@ public class WindowManagerService extends IWindowManager.Stub
                 + ", lastOrientation=" + mLastOrientation);
         }
 
-        int oldRotation = mRotation;
-
         mRotation = rotation;
         mAltOrientation = altOrientation;
         mPolicy.setRotationLw(mRotation);
@@ -6859,7 +6895,6 @@ public class WindowManagerService extends IWindowManager.Stub
         mH.removeMessages(H.WINDOW_FREEZE_TIMEOUT);
         mH.sendEmptyMessageDelayed(H.WINDOW_FREEZE_TIMEOUT, WINDOW_FREEZE_TIMEOUT_DURATION);
         mWaitingForConfig = true;
-        final DisplayContent displayContent = getDefaultDisplayContentLocked();
         displayContent.layoutNeeded = true;
         final int[] anim = new int[2];
         if (displayContent.isDimming()) {
@@ -6867,33 +6902,6 @@ public class WindowManagerService extends IWindowManager.Stub
         } else {
             mPolicy.selectRotationAnimationLw(anim);
         }
-        boolean rotateSeamlessly = mPolicy.shouldRotateSeamlessly(oldRotation, mRotation);
-        final WindowList windows = displayContent.getWindowList();
-        // We can't rotate seamlessly while an existing seamless rotation is still
-        // waiting on windows to finish drawing.
-        if (rotateSeamlessly) {
-            for (int i = windows.size() - 1; i >= 0; i--) {
-                WindowState w = windows.get(i);
-                if (w.mSeamlesslyRotated) {
-                    rotateSeamlessly = false;
-                    break;
-                }
-                // In what can only be called an unfortunate workaround we require
-                // seamlessly rotated child windows to have the TRANSFORM_TO_DISPLAY_INVERSE
-                // flag. Due to limitations in the client API, there is no way for
-                // the client to set this flag in a race free fashion. If we seamlessly rotate
-                // a window which does not have this flag, but then gains it, we will get
-                // an incorrect visual result (rotated viewfinder). This means if we want to
-                // support seamlessly rotating windows which could gain this flag, we can't
-                // rotate windows without it. This limits seamless rotation in N to camera framework
-                // users, windows without children, and native code. This is unfortunate but
-                // having the camera work is our primary goal.
-                if (w.isChildWindow() & w.isVisibleNow() &&
-                        !w.mWinAnimator.mSurfaceController.getTransformToDisplayInverse()) {
-                    rotateSeamlessly = false;
-                }
-            }
-        }
 
         if (!rotateSeamlessly) {
             startFreezingDisplayLocked(inTransaction, anim[0], anim[1]);
@@ -6906,6 +6914,10 @@ public class WindowManagerService extends IWindowManager.Stub
             // When we are rotating seamlessly, we allow the elements to transition
             // to their rotated state independently and without a freeze required.
             screenRotationAnimation = null;
+
+            // We have to reset this in case a window was removed before it
+            // finished seamless rotation.
+            mSeamlessRotationCount = 0;
         }
 
         // We need to update our screen size information to match the new rotation. If the rotation
@@ -8921,8 +8933,8 @@ public class WindowManagerService extends IWindowManager.Stub
                             if (w.mSeamlesslyRotated) {
                                 layoutNeeded = true;
                                 w.setDisplayLayoutNeeded();
+                                markForSeamlessRotation(w, false);
                             }
-                            w.mSeamlesslyRotated = false;
                         }
                         if (layoutNeeded) {
                             mWindowPlacerLocked.performSurfacePlacement();
@@ -11508,6 +11520,26 @@ public class WindowManagerService extends IWindowManager.Stub
         mPolicy.registerShortcutKey(shortcutCode, shortcutKeyReceiver);
     }
 
+    void markForSeamlessRotation(WindowState w, boolean seamlesslyRotated) {
+        if (seamlesslyRotated == w.mSeamlesslyRotated) {
+            return;
+        }
+        w.mSeamlesslyRotated = seamlesslyRotated;
+        if (seamlesslyRotated) {
+            mSeamlessRotationCount++;
+        } else {
+            mSeamlessRotationCount--;
+        }
+        if (mSeamlessRotationCount == 0) {
+            if (DEBUG_ORIENTATION) {
+                Slog.i(TAG, "Performing post-rotate rotation after seamless rotation");
+            }
+            if (updateRotationUncheckedLocked(false)) {
+                mH.sendEmptyMessage(H.SEND_NEW_CONFIGURATION);
+            }
+        }
+    }
+
     private final class LocalService extends WindowManagerInternal {
         @Override
         public void requestTraversalFromDisplayManager() {

services/core/java/com/android/server/wm/WindowStateAnimator.java

@@ -1431,7 +1431,7 @@ class WindowStateAnimator {
         // If we are undergoing seamless rotation, the surface has already
         // been set up to persist at it's old location. We need to freeze
         // updates until a resize occurs.
-        w.mSeamlesslyRotated = w.mSeamlesslyRotated && !mSurfaceResized;
+        mService.markForSeamlessRotation(w, w.mSeamlesslyRotated && !mSurfaceResized);
 
         calculateSurfaceWindowCrop(mTmpClipRect, mTmpFinalClipRect);
 
@@ -2156,7 +2156,7 @@ class WindowStateAnimator {
             cropRect.set(0, 0, w.mRequestedWidth, w.mRequestedWidth + w.mRequestedHeight);
             mSurfaceController.setCropInTransaction(cropRect, false);
         } else {
-            w.mSeamlesslyRotated = true;
+            mService.markForSeamlessRotation(w, true);
             transform.getValues(mService.mTmpFloats);
 
             float DsDx = mService.mTmpFloats[Matrix.MSCALE_X];